In the sampling of molten metal, pneumatic samplers have been developed to withdraw molten metal into a sample cavity without complete immersion of the cartridge. Pat. Nos. 3,791,220; 3,905,238; and 3,996,803 disclose pneumatic samplers in which the pressure is reduced in the mold cavity to effect evacuation of the molten metal into the mold cavity. Although pneumatic samplers of the types illustrated in the foregoing patents have particular advantages in certain applications and for certain categories of metal melts, there are some disadvantages. Molten metal can run out the fill tube during and after withdrawal from the bath and shrinkage cavities can occur. Furthermore, voids can occur in the sample.
Side entry port sampling cartridges such as that shown in U.S. Pat. No. 3,481,201, and particularly that illustrated in FIG. 5 of that patent, provide good samples and there is no loss of molten metal as the sample cartridge is withdrawn from the melt. The top filling of the sample eliminates voids in the sample. In addition, side fill cartridges tend to minimize the shrinkage cavity.